XINLI BOILER

Prevention and mitigation methods of biomass boiler stoppage corrosion

10 Jan, 2022

　　In order to prevent or reduce the corrosion of biomass boilers from shutdown, shutdown protection measures should be adopted. There are many methods of shutdown protection, mainly divided into two categories: wet protection and dry protection.

　　Wet protection is often used for short periods of inactivity, such as within one month. The common method of wet protection is to fill the boiler with deoxygenated water or an aqueous solution containing alkali and maintain a pressure of 0.3 to 0.5Mpa to prevent air leakage.

　　If the furnace has been shut down for a long time or the weather is cold, dry protection should be used to prevent freezing damage to the equipment. The method is to discharge all the boiler water when the water temperature drops to 70~80℃ after stopping the boiler, use the residual heat of the boiler to evaporate all the water in the heating surface, and use compressed air to blow off all the water vapor in the furnace that has not been dried. , And then place a container of anhydrous calcium chloride in the steam drum. Put calcium chloride in the ratio of 0.5~1.0L per cubic meter of water volume (calculated as 2kg/m3 if quicklime is used), then close the manhole, check regularly, and replace the desiccant when it is found to be powdery.

　　can also be filled with ammonia or nitrogen for protection, the preparation is the same as with desiccant. Because ammonia gas is lighter than air, when filling ammonia for protection, ammonia gas should be taken in from the upper part and air should be discharged from the lower part. Nitrogen is slightly lighter than air. Nitrogen can also be introduced from the upper part and exhausted from the lower part. In order to prevent air leakage, the pressure should be maintained at 0.3~0.5Mpa, and ammonia or nitrogen should be added in time when the pressure drops.